Donald Trump, aiming to close the deal in Iowa, unleashed a relentless attack on his closest rival Ted Cruz on Thursday while pitching himself as a unifier who can bridge the divides President Barack Obama has torn open.

The billionaire businessman ratcheted up the assault on the Texas senator that he started once it became clear late last year that Cruz was nipping at his heels in Iowa. He started the day bashing him on Twitter, retweeting a digitally warped image of a balding Cruz and mocking him for hitting the trail with “wacko” Glenn Beck — whom he called a poor substitute for his own companion, Sarah Palin. He doubled down later in the day at a Las Vegas rally, calling Cruz too “strident” to close deals in Washington.

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“Here’s a United States senator, Republican, doesn’t have the support of one other Republican senator. There’s something wrong there. And I can tell you, they like me — those guys,” Trump said. “We gotta make deals, we don’t want to sign executive orders."

Even as he delivered these scathing critiques, Trump released a video presenting himself as the ultimate unifier.

"Our country is totally divided. There's so much hatred. There's so many problems," Trump says in the video released on Facebook, as various images flash across the screen, including people reacting to the death of Trayvon Martin, protesters outside the White House clad in orange jumpsuits and black hoods protesting the detention of prisoners at Guantánamo Bay, and the unrest in Ferguson, Missouri, in 2014, following the police shooting of Michael Brown.

"Our president was a terrible unifier. He was the opposite of a unifier. He was a divider," Trump continued. "I will unify and bring our country back together. It's something I've done all of my life."

The all-out assault on Cruz shows some signs of paying off. While Cruz zoomed past Trump in Iowa in mid-December, a new CNN/ORC poll released Thursday shows Trump back up on top in the state with less than two weeks before the Iowa caucuses.

The survey showed Trump with a double-digit lead over Cruz (37 percent to 26 percent), with 46 percent of Republican voters saying Trump has the best chance to win the general election, compared with 27 percent who say the same about Cruz.

But Cruz is not taking the abuse laying down. While Cruz used to pull his punches with Trump — an attempt to not alienate his voters who might drift his way — the Texas senator has done away with the sweet talk.

Asked during a Boston Herald Radio interview on Thursday morning whether he and Trump were ever actually friends, Cruz remarked that Trump could speak for himself, offering backhanded praise of him as "an amazing marketer."

He went on to challenge the business mogul's conservative bona fides, pummeling him for his past support of traditionally liberal stances on issues like abortion and immigration reform. He said the "language he's saying on the campaign trail ... does not match how he lived the first 60 years of his life."

"The first 60 years of his life, he supported partial-birth abortion. Now, suddenly, when he's a candidate for president, he claims to be pro-life," the senator said. "OK. But as a voter, I've seen enough people, enough candidates, enough politicians say things on the campaign trail that they didn't follow through on, that when every one of his campaign promises is directly opposite where his record was, that's troubling."

The radio hit followed some slams Cruz delivered earlier in the morning, when he claimed Trump supported amnesty for undocumented immigrants in the past, sharing a tweet from the businessman from August 2013.

"Trump SUPPORTS amnesty. Read his 2013 tweet — while I was leading the fight to defeat Rubio Gang of 8 amnesty. #Truth" Cruz tweeted, referring to a Trump's proclamation at the time that "Congress must protect our borders first. Amnesty should be done only if the border is secure and illegal immigration has stopped."

Cruz also grinded away at a new line of attack against Trump that he debuted this week — that Trump is doing the establishment's bidding. It reflects just how much Trump's entrance into the race screwed with Cruz's intended pitch of himself as the rabble-rousing outsider who has proved that he doesn't play by Washington's rules.

The Texas senator pushed the line again on Thursday morning, saying the establishment is bolting from Marco Rubio for Trump.

"What I can tell you is the lobbyists in Washington, the big financiers, the banks who have given Donald Trump billions of dollars, they're all scurrying to get behind Donald because, as they say, he's someone we can make a deal with," Cruz told Boston Herald Radio.

He also argued that his earlier tweet about Trump supporting amnesty underscores a "sharp difference." Cruz added, "I get on the presidential campaign he suddenly discovered illegal immigration is a problem. But you know, then, we were actually fighting against amnesty, Donald Trump was criticizing Mitt Romney for being too tough on illegal immigration. He thought Mitt Romney needed to be softer on illegal immigration. And that's why the New Hampshire primary is so valuable, because the men and women of this state take really seriously the obligation not just to listen to the rhetoric but to look to the records and look candidates in the eye."

As far as Palin's endorsement of Trump, Cruz was quick to note that he did not consider the former governor of Alaska and 2008 GOP vice-presidential nominee a part of the political establishment.

But in an attempt to further get under Cruz’s skin, Trump further needled him on Palin, who played a pivotal role in Cruz’s election to the Senate in 2012.

“If it weren’t for Sarah Palin, he would not be a senator,” Trump said. “He was at 2 percent then she came on and he did fine.”

He went on to really grind in the insult, while trying to twist Cruz’s own “establishment” attack back against him. “Guys like Ted Cruz will never make a deal because he’s a strident guy,” Trump said. “He’s trying to paint me as part of the establishment and somebody said ‘establishment? Well how come Sarah Palin just backed him?'”